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Groups > linux.kernel > #1468119
| From | Brian Gerst <brgerst@gmail.com> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: [PATCH 5/8] x86/head: remove useless zeroed word |
| Date | 2016-08-23 01:00 +0200 |
| Message-ID | <s96md-40p-3@gated-at.bofh.it> (permalink) |
| References | <s7Bkt-3Yh-9@gated-at.bofh.it> <s7Bkt-3Yh-7@gated-at.bofh.it> <s95gt-3lP-11@gated-at.bofh.it> <s95Tb-3OC-13@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
On Mon, Aug 22, 2016 at 6:23 PM, H. Peter Anvin <hpa@zytor.com> wrote: > On August 22, 2016 2:48:46 PM PDT, Andi Kleen <andi@firstfloor.org> wrote: >>Josh Poimboeuf <jpoimboe@redhat.com> writes: >> >>> This zeroed word has no apparent purpose, so remove it. >>> >>> Brian Gerst says: >>> >>> "FYI the word used to be the SS segment selector for the LSS >>> instruction, which isn't needed in 64-bit mode." >>> >> >>Seems dangerous. It wouldn't surprise me if some CPUs or x86 emulations >>load it anyways and trigger page faults if there is really nothing >>there. >> >>-Andi > > Yes, seems pointlessly risky. It was added in commit 9cf4f298e29abba25c16679fe7be70898223167e, copied from 32-bit but never used. It doesn't look like we ever used LSS on 64-bit. -- Brian Gerst
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[PATCH 5/8] x86/head: remove useless zeroed word Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-18 21:40 +0200
Re: [PATCH 5/8] x86/head: remove useless zeroed word Andi Kleen <andi@firstfloor.org> - 2016-08-22 23:50 +0200
Re: [PATCH 5/8] x86/head: remove useless zeroed word "H. Peter Anvin" <hpa@zytor.com> - 2016-08-23 00:30 +0200
Re: [PATCH 5/8] x86/head: remove useless zeroed word Brian Gerst <brgerst@gmail.com> - 2016-08-23 01:00 +0200
Re: [PATCH 5/8] x86/head: remove useless zeroed word "H. Peter Anvin" <hpa@zytor.com> - 2016-08-23 01:20 +0200
Re: [PATCH 5/8] x86/head: remove useless zeroed word Linus Torvalds <torvalds@linux-foundation.org> - 2016-08-23 01:10 +0200
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